US4393429A - Superconductive coil system with protecting device - Google Patents
Superconductive coil system with protecting device Download PDFInfo
- Publication number
- US4393429A US4393429A US06/257,375 US25737581A US4393429A US 4393429 A US4393429 A US 4393429A US 25737581 A US25737581 A US 25737581A US 4393429 A US4393429 A US 4393429A
- Authority
- US
- United States
- Prior art keywords
- superconductive coil
- motor
- coil
- superconductive
- protecting device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F6/00—Superconducting magnets; Superconducting coils
- H01F6/006—Supplying energising or de-energising current; Flux pumps
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/001—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for superconducting apparatus, e.g. coils, lines, machines
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/10—Nuclear fusion reactors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S505/00—Superconductor technology: apparatus, material, process
- Y10S505/825—Apparatus per se, device per se, or process of making or operating same
- Y10S505/85—Protective circuit
Definitions
- the present invention relates to a superconductive coil system for use in a nuclear fusion plant or a magnetic train floating system, and more particularly to a superconductive coil system which is equipped with a protecting device in a quenching operation.
- the superconductive coil is energized by a d.c. motor through a current switch when in a normal running operation.
- the current switch is turned off so that a portion of the magnetic energy owned by the superconductive coil is consumed as the Joule heat of a protecting resistor which is connected in parallel with the superconductive coil.
- the heat generation in terms of the Joule heat of the superconductive coil is reduced.
- R R c +R s ;
- R s Resistance after the quenching operation of the superconductive coil
- R c Resistance of the protecting resistor
- I 0 Energizing Current in the normal operation
- the ratio P r of the energy to be consumed by the superconductive coil to the magnetic energy of the superconductive coil is expressed by the following Equation if the resistance R s of the superconductive coil after the quenching operation is assumed to be constant: ##EQU1##
- the allowable withstand voltage of the superconductive coil is generally low, e.g., 1 to 2 KV at the highest, there arises a defect that the heat generation percentage of the superconductive coil becomes high and reaches 20 to 30% or more.
- Another object of the present invention is to provide a superconductive coil which has its heat generation reduced when in the quenching operation and which is highly reliable.
- a d.c. motor is connected between the terminals of a superconductive coil through a unidirectional current gate device so that the magnetic energy of the superconductive coil may be partially converted into the rotational energy of a d.c. motor when in the quenching operation of the superconductive coil.
- FIG. 1 is an electric circuit diagram showing one embodiment of the present invention
- FIG. 2 is a current and voltage waveform chart for explaining the operations of FIG. 1;
- FIG. 3 is a sectional view schematically showing a unipolar motor to be used in FIG. 1;
- FIG. 4 is a chart showing the change of the constant of the circuit shown in FIG. 1;
- FIGS. 5 to 8 are electric circuit diagrams showing other embodiments of the present invention.
- a protecting device 12 is connected between both the terminals of a superconductive coil 10.
- the protecting device 12 is constructed of a series circuit which is composed of a unidirectional current gate device, e.g., a diode 14 and a d.c. motor 16.
- the conductive direction of the unidirectional current gate device 14 is so preset that a current i continuously flows through a closed circuit, which is constructed of the superconductive coil 10, the d.c. motor 16 and the unidirectional current gate device 14, when a current switch 18 is turned off in the quenching operation of the superconductive coil 10. That current i will continuously flow until the magnetic energy of the superconductive coil 10 is reduced to zero.
- the d.c. motor 16 is equivalently expressed by the series circuit which is composed of a capacitor C 0 for storing a voltage corresponding to an induction voltage, an internal inductance L 0 and an internal resistor R 0 .
- the current switch 18 When the superconductive coil 10 is quenched, the current switch 18 is turned off so that the current to flow through the superconductive coil 10 starts to be reduced. According to this, the terminal voltage e is generated by the term of L(di/dt) in the opposite direction to that in the normal running operation so that the current i continuously flows through the d.c. motor by way of the unidirectional current gate device 14. In other words, the path of the current to flow through the superconductive coil 10 is instantly shifted from the d.c. power source to the d.c. motor by turning the current switch 18.
- R R s +R 0 : Total resistance of the circuit.
- Equation (4) the value i in the Equation (4) is expressed, as follows. (Here, the relationships of 2/R ⁇ L/C 1 is taken to generate an oscillatory current). ##EQU2## where, ##EQU3##
- the waveforms of the current i and voltage e of the superconductive coil which are expressed by the Equations (9) and (10), are drawn in FIG. 2. As shown, the current i is decreased generally in the form of a sine wave, whereas the voltage e is increased generally in the form of a sine wave. Now, if it were not for the unidirectional current gate device 14, the current i and the voltage e oscillate positively and negatively. As a result, the magnetic energy of the superconductive coil 10 repeats at most the conversion into the magnetic energy of the d.c. motor and the reconversion into the magnetic energy of that coil so that the magnetic energy of the superconductive coil becomes the heat generated thereby, whereby the function of the protecting device is not performed.
- the current i does not flow in the negative direction so that most of the magnetic energy of the superconductive coil 10 is converted into the rotational coil of the d.c. motor 16. Since the magnetic energy is stored as the rotational energy, it can be effectively reused for the re-energization of the superconductive coil 10.
- the unipolar motor shown in FIG. 3 is the most proper for use partly because its rotor has such a simple construction that it can rotate at a high speed and partly because the unipolar motor can store a high rotational energy.
- the stator of the unipolar motor is primarily constructed of a field winding 22, a yoke 24, an armature compensating conductor 26, current collectors 28 and bearings 30, whereas the rotor is primarily constructed of a cylindrical conductor 32. Since the cylindrical conductor is fabricated by joining the conductor of copper, aluminum or the like to the surface of copper or steel, it has no slot so that it has a simple construction suitable for high speed rotations.
- the equivalent capacitance C 0 of the unipolar motor can be expressed by the following Equation: ##EQU7## where, e 0 and i 0 : Induced voltage and current of the unipolar motor;
- r and l Radius and length of the rotor.
- the adjustment of the equivalent capacitance value of the unipolar motor can be performed by changing the size of the rotor and the density of the field magnetic flux (ie., the field current).
- FIG. 4 shows the characteristics of the term P r E m /R s I 0 to the value k, which are obtained from the Equation (16).
- the performance can be improved more than that of the prior art, if the value k is selected within a predetermined range.
- FIG. 5 shows another embodiment, in which a d.c. motor 38 forming part of the protecting device when in the quenching operation of a superconductive coil 36 is made to act as a steady energizing power source. Since, in this embodiment, the protecting device instantly operates when in the quenching operation of the superconductive coil 36, the Joule loss does not take place only in the superconductive coil during a time period (generally about 0.1 to 0.3 seconds) until the current switch is turned off so that the heat generated by the coil is reduced. Moreover, the d.c. power source for the steady energization and the current switch can be dispensed with.
- FIG. 6 shows a further embodiment, in which a resistor 44 is connected in series between a d.c. motor 40 and a unidirectional current gate device 42.
- a resistor 44 is connected in series between a d.c. motor 40 and a unidirectional current gate device 42.
- FIG. 7 shows a further embodiment, in which the equivalent capacitance C 0 of a d.c. motor 48 is made variable during the protecting operation.
- the equivalent capacitance C 0 of a d.c. motor 48 is made variable during the protecting operation.
- a controller 52 is provided to detect the terminal voltage of the superconductive coil 50, to adjust the field current of the d.c. motor 48 and to vary the equivalent capacitance C 0 which is expressed by the Equation (14).
- FIG. 8 shows a further embodiment, in which there are connected in parallal with a superconductive coil 54 both a series circuit composed of a d.c. motor 56 and a unidirectional current gate device 58, and a resistor 60. Since the magnetic energy of the superconductive coil is converted into both the Joule loss of the protecting resistor and the rotational energy of the d.c. motor, there can be attained according to that embodiment an effect that the heat generation of the coil is reduced.
- one terminal of the protecting resistor 60 is connected with the cathode of the unidirectional current gate device 58 but may be connectd with the anode of the same.
Abstract
Description
L(di/dt)+Ri=0
i=I.sub.0 e.sup.-(R/L)t ( 1)
e=E.sub.m.e.sup.-(R/L)t ( 2)
1/C∫idt+L(di/dt)+Ri=0 (4)
e=-L.sub.s (di/dt)=(L.sub.s I.sub.o /β.sub.1 LC)e.sup.-α.sbsp.1.spsp.t sin (2θ.sbsp.1-β.sbsp.1t) (6)
t.sub.0 =θ.sub.1 /β.sub.1 (8);
P.sub.r E.sub.m /R.sub.c I.sub.o =R.sub.s /(R.sub.c +R.sub.s) (15)
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP55/53618 | 1980-04-24 | ||
JP5361880A JPS56150805A (en) | 1980-04-24 | 1980-04-24 | Protective device of superconducting coil |
Publications (1)
Publication Number | Publication Date |
---|---|
US4393429A true US4393429A (en) | 1983-07-12 |
Family
ID=12947888
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/257,375 Expired - Lifetime US4393429A (en) | 1980-04-24 | 1981-04-24 | Superconductive coil system with protecting device |
Country Status (3)
Country | Link |
---|---|
US (1) | US4393429A (en) |
JP (1) | JPS56150805A (en) |
DE (1) | DE3116251A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4855859A (en) * | 1987-03-30 | 1989-08-08 | Societe Anonyme Dite Alsthom | Detection device for detecting transitions to the normal state in a superconducting winding, in particular for generating electricity, and a protection device for protecting such a winding |
US4956740A (en) * | 1987-08-04 | 1990-09-11 | Massachusetts Institute Of Technology | Protection technique for superconducting magnets |
WO1993007851A1 (en) * | 1991-10-25 | 1993-04-29 | Church & Dwight Company, Inc. | Buffering system for anticalculus dentifrices |
US5644218A (en) * | 1995-02-01 | 1997-07-01 | Superconductivity, Inc. | Protection device for a superconducting coil of a superconducting voltage stabilizer |
US11557893B2 (en) | 2015-09-09 | 2023-01-17 | Tokamak Energy Ltd | Quench protection in superconducting magnets |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5899407A (en) * | 1981-12-07 | 1983-06-13 | Kanebo Ltd | Emulsion type cosmetic |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3304466A (en) * | 1965-04-20 | 1967-02-14 | Gen Electric | Protective circuits for superconductive loads |
US3305699A (en) * | 1965-03-08 | 1967-02-21 | Gen Electric | Protective circuit for superconductive loads |
US3711744A (en) * | 1972-06-01 | 1973-01-16 | Atomic Energy Commission | Passive energy dump for superconducting coil protection |
-
1980
- 1980-04-24 JP JP5361880A patent/JPS56150805A/en active Granted
-
1981
- 1981-04-23 DE DE19813116251 patent/DE3116251A1/en not_active Withdrawn
- 1981-04-24 US US06/257,375 patent/US4393429A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3305699A (en) * | 1965-03-08 | 1967-02-21 | Gen Electric | Protective circuit for superconductive loads |
US3304466A (en) * | 1965-04-20 | 1967-02-14 | Gen Electric | Protective circuits for superconductive loads |
US3711744A (en) * | 1972-06-01 | 1973-01-16 | Atomic Energy Commission | Passive energy dump for superconducting coil protection |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4855859A (en) * | 1987-03-30 | 1989-08-08 | Societe Anonyme Dite Alsthom | Detection device for detecting transitions to the normal state in a superconducting winding, in particular for generating electricity, and a protection device for protecting such a winding |
US4956740A (en) * | 1987-08-04 | 1990-09-11 | Massachusetts Institute Of Technology | Protection technique for superconducting magnets |
WO1993007851A1 (en) * | 1991-10-25 | 1993-04-29 | Church & Dwight Company, Inc. | Buffering system for anticalculus dentifrices |
GB2275872A (en) * | 1991-10-25 | 1994-09-14 | Church & Dwight Co Inc | Buffering system for anticalculus dentifrices |
GB2275872B (en) * | 1991-10-25 | 1995-07-12 | Church & Dwight Co Inc | Buffering system for anticalculus dentifrices |
US5644218A (en) * | 1995-02-01 | 1997-07-01 | Superconductivity, Inc. | Protection device for a superconducting coil of a superconducting voltage stabilizer |
US11557893B2 (en) | 2015-09-09 | 2023-01-17 | Tokamak Energy Ltd | Quench protection in superconducting magnets |
Also Published As
Publication number | Publication date |
---|---|
JPS56150805A (en) | 1981-11-21 |
DE3116251A1 (en) | 1982-04-08 |
JPS6156854B2 (en) | 1986-12-04 |
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